Author of a model, Felix Klein (1849 — 1925) proposed “Erlangen Program” [1]} — the
unified view over different geometries as complex of different transformation groups of space. The
invariants of these groups are figures of the geometries. In such way, Klein presented 9 two–dimensional
spaces. However, 6 of them he considered practic unaplicable [2]}. Till now speaking about
“non–euclidean geometry”, elliptic or hyperbolic geometry is primarily understood. Obviously, in order
to make all geometries to be taken seriously, an accessible model is required. One of such model for
two–dimensional case proposed [3]} Isaak Moiseevich Yaglom (1921 — 1988), using the notion
of generalized complex number. Among more recent results you can refer to [4]}, [5]}, [6]}.
